public class FindSimilarIdeasController {

   public static void test() {
      // Instantiate a new idea  
    
      Idea idea = new Idea ();

      // Specify a title for the new idea 
    
      idea.Title = 'Increase Vacation Time for Employees';

      // Specify the communityID (INTERNAL_IDEAS) in which to find similar ideas.  
    
      Community community = [ SELECT Id FROM Community WHERE Name = 'INTERNAL_IDEAS' ];

      idea.CommunityId = community.Id;

      ID[] results = Ideas.findSimilar(idea);
   }
}